Chemical Pathways

Food is your source of energy!Calorie-amount of energy needed to raise the

temperature of 1 gram of water 1 degree Celsius1 kilocalorie is 1000 caloriesKilocalories are actually on the food package but we

call it CALORIESCells use calories from food to make ATP

Cellular energyBreak off the phosphate molecules and we release energyForm ADP

ADP is made back into ATP through cell respirationPlants and animals carrying out cell respiration.

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Cell Respiration Overview Release energy by breaking down glucose

and other food molecules with the help of oxygen

EquationOxygen + glucose= carbon dioxide + water+

ATPTake place in the mitochondriaTwo types of respiration:

Anaerobic-does not use oxygenAerobic-uses oxygen

GlycolysisTakes place in the

cytoplasm of the cellINPUTS: Glucose and

2 molecules of ATPOUTPUTS: 4 ATP (net

gain of 2) and pyruvic acid

NADH holds electrons for later use to create tons of energyCalled an electron

carrier

FermentationIf oxygen is not present, fermentation takes

place after glycolysisFermentation-releases ATP from food

without the use of oxygenTwo main types

Alcoholic fermentation-yeast form ethyl alcohol and carbon dioxide as waste; cause bread dough to rise

Lactic acid fermentation-lactic acid is producedCreated when your muscles do not have enough

oxygen to produce ATP when exercisingo Buildup of lactic acid creates a painful burning

sensationUnicellular organisms use to make food like

yogurt, cheese, sour cream, pickles, sauerkraut

Section 9.2 Kreb Cycle (citric acid cycle)

Pathway is aerobic-needs oxygen to function

Pyruvic acid from glycolysis enters the mitochondria

Carbon is removed from this acid to form carbon dioxide

Pyruvic acid will turn into acetyl CoA

Acetyl CoA will turn into citric acid

Citric acid goes through the cycle to form ATP, carbon dioxide, NADH and FADH2 (these two items hold high energy electrons that will be used in the next cycle)

Electron Transport ChainNADH and FADH2 is

passed to this stage in the membrane of the mitochondria

The electrons that are in these two molecules are passed along the carrier proteins in the membrane

Water will form at the end of this chain

Kreb and electron transport chain produce 36 ATP per one molecule of glucose

We don’t always consume glucose so how do we make ATP?Complex carbohydrates are broken down

into glucose.Lipids and proteins can be broken down

into molecules that enter the Kreb cycle and electron transport chain

Energy and exerciseQuick energy

Enough ATP for a short timeRest of time ATP is produced by lactic acid

fermentationAfter race, heavy breathing is used to increase

oxygen to repay the oxygen debtLong term energy

For exercise that is 90 seconds or longer, body relies on cell respiration

Use stored energy in the form of glycogenBody will begin to break down other stored

molecules like fat